Studies on Rooting in Vitro and Transfer of Betula pendula Superior Clones from Germany

It has been proposed that there were many factors affecting Betula pendula clone seedling rooting in vitro.Genotype is an important factor which influence the ability of shoot rooting.The results demonstrated that clone 2/86 had the highest rooting ability,while G1 had the lowest rooting ability among all the tested materials.1/2 MS medium was the most suitable for multiplied shoot rooting.For the clone 4N,NAA alone was enough to induce multiplied shoot rooting and the suitable concentration of NAA was 0.3 mg/L.Whereas for the clone 1/86 or 2/86,1/2 MS medium supplemented with 0.1mg/L NAA and(0.1) mg/L IBA was optimum.Percentage of rooting is related to wooden level of B.pendula seedling,and the more the wooden,the less the percentage of rooting.The plantlets in vitro were finally transferred to soil with 1/3 humus soil+1/3 sand+1/3 stand soil or 2/3 humus soil +1/3 stand soil.The days when plantlets cultured in rooting medium and growth status of the rooting plantlets were key factors to improve the survival rate of plantlets.The highest survival rate of transplant was in the period of quickest elongating of adventitious root.